The most efficient, stable, and easy-to-synthesize non-noble metal catalyst system for the reduction of CO(2) and bicarbonates is presented. In the presence of the iron(II)-fluoro-tris(2-(diphenylphosphino)phenyl)phosphino]tetrafluoroborate complex 3, the hydrogenation of bicarbonates proceeds in good yields with high catalyst productivity and activity (TON > 7500, TOF > 750). High-pressure NMR studies of the hydrogenation of carbon dioxide demonstrate that the corresponding iron-hydridodihydrogen complex 4 is crucial in the catalytic cycle.

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A novel iron-catalyzed hydrogenation of nitroarenes to the corresponding amines is reported. An in situ combination of Fe(BF4)2·6H2O and phosphine allows for highly selective hydrogenation of a broad range of aromatic and nitroarenes tolerating different functional groups.

A convenient and selective oxidation of alcohols with hydrogen peroxide to give aldehydes and ketones has been developed. Using in situ generated iron chloride complexes [Fe(L3) 2 Cl n ] [n= 0-1, L3 = 6-(N-phenylbenzimidazoyl)-2-pyridinecarboxylic acid], aldehydes and ketones were obtained in good yield and excellent selectivity after a short reaction time at room temperature.

Scheme 1.Steps in the hydrogenation of oxalic acid esters.

New benzoyl- and naphthoyl-substituted phosphines have been synthesized, which are stable to air and moisture. Testing these so-called phosphomide ligands in the presence of different ruthenium precursors, the hydrogenation of sodium bicarbonate (NaHCO(3)) to sodium formate (NaHCO(2)) proceeded with good catalyst turnover numbers in the range of 1300-1600 at 80°C and a total pressure of hydrogen of 60 bar in the absence of amines or other additives. Similarly, catalytic hydrogenations of carbon dioxide, cinnam-, and benzaldehyde were possible with these new ruthenium complexes. As an intermediate of the catalytic cycle the defined ruthenium complex [(η(6)-C(6)H(6))-RuCl(2)(Cy(2)P(1-naphthoyl)] (Cy=cyclohexyl) was prepared and characterized by X-ray crystallography.

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Hydrogenation of Nitroarenes Using Defined Iron-Phosphine Catalysts. -A novel, highly chemoselective hydrogenation of nitroarenes to corresponding amines (18 examples) is developed. -(WIENHOEFER, G.; BASEDA-KRUEGER, M.; ZIEBART, C.; WESTERHAUS, F. A.; BAUMANN, W.; JACKSTELL, R.; JUNGE, K.; BELLER*, M.; Chem. Commun. (Cambridge) 49 (2013) 80, 9089-9091, http://dx.